Pro PayPal Soap 1.1 or 1.2 Specs

If I plan to add paypal options for payment to an existing e-commerce site already providing general merchant services (which is neither SOAP architecture or XML-RPC), which release of the SOAP specification does PayPal e-commerce support?

My assumption is PayPal is using SOAP, therefore do the API Transactions send back error messages in the event the transaction failed or if portions of the paypal services are not available? Does PayPal use SOAP Fault Messages for this return information?

Does the book go into some detail in these areas or similiar?

My apology for duplicate posts. hopefully the administrators can delete this first post! *.javaranch.com seems to be experiencing problems.

We do not use SOAP Faults, we return error codes along with a "short message" and a "long message".

Not sure about the SOAP version number.